Assimilate Source-Sink Relationships in Capsicum annuum L. I. The Dynamics of Growth in Fruiting and Deflorated Plants

Abstract

The shaded fruit of the pepper plant was the main sink for assimilates during much of the growth period of this organ. Up to 90 % of the plant daily dry weight increase was deposited in the fruit, and growth of all non-fruit organs was correlatively reduced. No net transfer of dry matter from other organs to the fruit could be detected. In continuously deflorated plants, the partitioning of dry matter among organs was more evenly balanced. Net assimilation rates of fruiting plants exceeded those of deflorated plants, and these differences appeared to be associated with alterations in assimilate demand. Net assimilation rates of fruiting plants remained constant for up to 40 days under conditions of very little leaf surface turnover, indicating that leaves of these plants retain their photosynthetic capacity long after full expansion. Foliar senescence and abscission in deflorated plants was marked, but these processes were inhibited during the growth of the fruit. Some possible causes of this differential response are considered.